How do we cache http response with koa?
How do we cache http response with koa?
1 answer
by
arnoldo.moen ,
2 years ago
@muriel.schmidt
In Koa, you can cache HTTP responses using various middleware and techniques. Here are a few approaches you can take:
- Koa-etag: The koa-etag middleware calculates and generates an ETag for an incoming response and adds it as the ETag header. It also handles the If-None-Match header for cache validation. You can install it using npm:
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npm install koa-etag |
To use it in your Koa application:
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const Koa = require('koa');
const etag = require('koa-etag');
const app = new Koa();
app.use(etag());
// Your routes and middleware
app.listen(3000);
|
- Koa-static-cache: This middleware caches static files (e.g., CSS, JavaScript, images) by adding the Cache-Control and Last-Modified headers. It allows the client to send a conditional GET request with the If-Modified-Since header. You can install it using npm:
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npm install koa-static-cache |
To use it in your Koa application:
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const Koa = require('koa');
const staticCache = require('koa-static-cache');
const app = new Koa();
app.use(staticCache(path.join(__dirname, 'public'), {
maxAge: 365 * 24 * 60 * 60, // Cache for 1 year
}));
// Your routes and middleware
app.listen(3000);
|
- Custom caching: You can implement your own caching logic using Koa's middleware. Here's an example of caching a response for a specific duration:
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const Koa = require('koa');
const app = new Koa();
// Cache middleware
app.use(async (ctx, next) => {
// Generate a unique cache key
const cacheKey = ctx.url;
// Check if cache key exists
const cachedResponse = cache.get(cacheKey);
if (cachedResponse) {
// Serve the cached response
ctx.body = cachedResponse;
return;
}
// Execute downstream middleware
await next();
// Cache the response for 5 minutes
cache.set(cacheKey, ctx.body, 5 * 60 * 1000);
});
// Your routes and middleware
app.listen(3000);
|
In the above example, the cache object represents a cache store (e.g., Redis, Memcached) that you can use to store and retrieve cached responses. Make sure you have a cache store installed and configured.
Remember to adjust the caching mechanism based on your application's needs and cache invalidation strategies.